Except for the inevitable suck-outs by the other guy, on the 'rare' occassion when I finish a SnG not ITM, I can usually identify the breaking of one or more of my personal playing rules as the cause. Of course, the beauty of any rule is that you must know when the RIGHT time is to break it... anyway, here is the list-in-progress:

1. Don't get involved in a hand unless the cards DEMAND that you do.
2. Full value from a hand is NOT as important as surviving until the next.
3. Don’t be PASSIVE and let the other guy catch his hand.
RESPECT early position raises, especially late in the game.
4. You need a BETTER HAND to call with than to raise with.
5. Don't call when you KNOW you are beat.
6. Don't call raises with Ax against a full table.
7. Treat playing poker like you are playing for a living.
8. Don't bluff too much.
9. Play to Survive.
10. Don't bet on the river when only a better hand can call.
11. Don't risk a lot to win a little.
12. Don't put advanced moves on novice players.
13. Don't play while tired or distracted.

Comments, additions, mockery, etc?